Scientific Outline


The EST's main mission is to observe the Sun. This star is a fundamental model for understanding the rest of the universe (all of the stars are suns). The Sun is the only star that can be studied in high resolution. The EST will look at the fundamental solar processes at their smallest scales, allowing us to analyse physical phenomena in the greatest possible detail.






The aperture of a telescope determines its resolving power. But, until recently, ground-based solar telescopes have been limited by wavefront distortion in the Earth's atmosphere. The advent of powerful adaptive optics techniques now allow for correction of most of this distortion. This makes it possible to capture the first glimpses of the solar surface fine structure, demonstrating that the technique is sufficiently mature and well developed. The resolving capability is now limited by telescope size only and not by atmospheric distortion. We can now look for answers to the fundamental questions of the physics of solar activity and its variability.

In addition to spatial resolution, the light collecting power of a large aperture is crucial for solar investigations. Magnetic fields are detected and characterized by analysing their imprint on the polarisation of light in suitably chosen spectral lines. The fraction of light that is polarised is very small (sometimes below 10^-3). The accuracy achieved in these polarimetric measurements, and therefore the ability to observe magnetic fields, is limited by the number of photons collected. With a large aperture, a greater number of photons can be detected in any given zone on the surface of the sun. This is vital to achieve the required accuracy for polarimetric measurements of 10^-4. The time scales determining changes in solar structures are related to the speed of sound (variable through the atmosphere, but typically around 7 km/s in the lower photosphere), in such a way that smaller structures evolve more quickly in time. The temporal resolution required is then just a few seconds, which can only accomplished by a large aperture telescope.

Together with the American DKIST, EST will fill a gap not covered by any other instrument, either ground-based or space-borne, currently existing or in the immediate future: it will be able to examine magnetic coupling in the solar atmosphere from the deepest layers of the photosphere to the highest layers of the chromosphere, to uncover the thermal, dynamic and magnetic properties of the sun's plasma at high spatial and temporal resolution. To do this the EST will need to specialise in high-precision polarimetry at many simultaneous wavelengths.



Canarias Avanza Logo

European Solar Telescope
C/ Via Láctea s/n 38200 La Laguna, Spain

Phone: +34 922 605 200

© Copyright EST 2020
Privacy policy

EST on Twitter EST on Twitter EST on Instagram EST on Instagram EST on LinkedIn